Here is the solution to get it working...
1. Ensure Tarannis is flashed to Flex Software
2. Flash r9mm to accst r9_mm_Flex_Fport.frk
3. solder in 5 volts + -
4. Solder inverted s.port to an open uart TX
5. In Beta Flight set selected uart to serial
6. in beta flight configuration set to s.bus...